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Forests, Volume 7, Issue 11 (November 2016)

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Open AccessArticle Modeling Anthropogenic Fire Occurrence in the Boreal Forest of China Using Logistic Regression and Random Forests
Forests 2016, 7(11), 250; doi:10.3390/f7110250
Received: 15 June 2016 / Revised: 13 October 2016 / Accepted: 18 October 2016 / Published: 25 October 2016
Cited by 3 | PDF Full-text (3705 KB) | HTML Full-text | XML Full-text
Abstract
Frequent and intense anthropogenic fires present meaningful challenges to forest management in the boreal forest of China. Understanding the underlying drivers of human-caused fire occurrence is crucial for making effective and scientifically-based forest fire management plans. In this study, we applied logistic regression
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Frequent and intense anthropogenic fires present meaningful challenges to forest management in the boreal forest of China. Understanding the underlying drivers of human-caused fire occurrence is crucial for making effective and scientifically-based forest fire management plans. In this study, we applied logistic regression (LR) and Random Forests (RF) to identify important biophysical and anthropogenic factors that help to explain the likelihood of anthropogenic fires in the Chinese boreal forest. Results showed that the anthropogenic fires were more likely to occur at areas close to railways and were significantly influenced by forest types. In addition, distance to settlement and distance to road were identified as important predictors for anthropogenic fire occurrence. The model comparison indicated that RF had greater ability than LR to predict forest fires caused by human activity in the Chinese boreal forest. High fire risk zones in the study area were identified based on RF, where we recommend increasing allocation of fire management resources. Full article
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Open AccessArticle Protective Effect of Nitric Oxide (NO) against Oxidative Damage in Larix gmelinii Seedlings under Ultraviolet-B Irradiation
Forests 2016, 7(11), 251; doi:10.3390/f7110251
Received: 12 August 2016 / Revised: 14 October 2016 / Accepted: 18 October 2016 / Published: 26 October 2016
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Abstract
Ultraviolet-B (UV-B) stress appears to be more striking than other research works because of the thin ozone layer. The protective influence of an exogenous nitric oxide donor and sodium nitroprusside (SNP) on the growth properties of Larix gmelinii seedlings was investigated under ultraviolet-B
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Ultraviolet-B (UV-B) stress appears to be more striking than other research works because of the thin ozone layer. The protective influence of an exogenous nitric oxide donor and sodium nitroprusside (SNP) on the growth properties of Larix gmelinii seedlings was investigated under ultraviolet-B radiation conditions. The results indicated that 0.1 mM SNP could effectively alleviate the damage caused by ultraviolet-B radiation, and improved the seedling growth properties, the relative water content, and photosynthetic pigment content in leaves. Additionally, the photosynthetic capacity and antioxidant enzyme activity were increased during the exposure. On the contrary, the damage caused by active oxygen was decreased in SNP-treated seedling leaves. The damage caused by ultraviolet-B radiation was slightly reduced after treating with 0.01 mM SNP. Nevertheless, treatment with 0.5 mM SNP had a negative effect under ultraviolet-B radiation. Furthermore, supplementing NO (nitric oxide) improved the photosynthetic capacity and antioxidant enzyme activity and alleviated the damage of caused by active oxygen. The best effective concentration of SNP was 0.1 mM. Therefore, a suitable amount of exogenous NO can protect the Larix gmelinii seedlings and increase their tolerance to ultraviolet-B radiation. Full article
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Open AccessArticle Automating Plot-Level Stem Analysis from Terrestrial Laser Scanning
Forests 2016, 7(11), 252; doi:10.3390/f7110252
Received: 25 August 2016 / Revised: 8 October 2016 / Accepted: 24 October 2016 / Published: 28 October 2016
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Abstract
Terrestrial laser scanning (TLS) provides an accurate means of analyzing individual tree attributes, and can be extended to plots using multiple TLS scans. However, multiple TLS scans may reduce the effectiveness of individual tree structure quantification, often due to understory occupation, mutual tree
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Terrestrial laser scanning (TLS) provides an accurate means of analyzing individual tree attributes, and can be extended to plots using multiple TLS scans. However, multiple TLS scans may reduce the effectiveness of individual tree structure quantification, often due to understory occupation, mutual tree occlusion, and other influences. The procedure to delineate accurate tree attributes from plot scans involves onerous steps and automated integration is challenging in the literature. This study proposes a fully automatic approach composed of ground filtering, stem detection, and stem form extraction algorithms, with emphasis on accuracy and feasibility. The delineated attributes can be useful to analyze terrain, tree biomass and fiber quality. The automation was experimented on a mature pine plot in Finland with both single scan (SS) and multiple scans (MS) datasets. With mensuration as reference, digital terrain models (DTM), stem locations, diameters at breast height (DBHs), stem heights, and stem forms of the whole plot were extracted and validated. Results of this study were best using the multiple scans (MS) dataset, where 76% of stems were detected (n = 49). Height extraction accuracy was 0.68 (r2) and 1.7 m (RMSE), and DBH extraction accuracy was 0.97 (r2) and 0.90 cm (RMSE). Height-wise stem diameter extraction accuracy was 0.76 (r2) and 2.4 cm (RMSE). Full article
(This article belongs to the Special Issue Forest Ground Observations through Terrestrial Point Clouds)
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Open AccessArticle Genetic Improvement of Wood Properties in Pinus kesiya Royle ex Gordon for Sawn Timber Production in Malawi
Forests 2016, 7(11), 253; doi:10.3390/f7110253
Received: 31 August 2016 / Revised: 23 October 2016 / Accepted: 25 October 2016 / Published: 27 October 2016
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Abstract
Accurate prediction of genetic potential and response to selection in breeding requires knowledge of genetic parameters for important selection traits. In this study, we estimated genetic parameters for wood properties in Khasi pine (Pinus kesiya Royle ex Gordon) grown in Malawi. Data
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Accurate prediction of genetic potential and response to selection in breeding requires knowledge of genetic parameters for important selection traits. In this study, we estimated genetic parameters for wood properties in Khasi pine (Pinus kesiya Royle ex Gordon) grown in Malawi. Data on wood properties and growth traits were collected from six families of Pinus kesiya at the age of 30. The results show that wood density had a higher genetic control (h2 = 0.595 ± 0.055) than wood stiffness (h2 = 0.559 ± 0.038) and wood strength (h2 = 0.542 ± 0.091). The genetic correlation among wood quality traits was significantly moderate (0.464 ± 0.061) to high (0.735 ± 0.025). The predicted genetic response indicated that selection for wood density at 10% selection intensity would increase stiffness and strength by 12.6% and 8.85%, respectively. The genetic correlations between growth and wood quality traits were moderately unfavourable. However, sufficient variation exists within the breeding population to select individuals with both good growth rate and high wood quality traits. It is therefore suggested that all trees with both diameter at breast height (DBH) greater than 32.0 cm and density greater than 0.593 g/cm3 must be selected in order to increase the efficiency of the breeding programme. However, in the long term, it is recommended that the best selection strategy would be to develop a multiple-trait selection index. The selection index should be developed using optimal index weights for the advanced Pinus kesiya breeding programme in Malawi. Full article
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Open AccessArticle Anthropogenic Disturbances Create a New Vegetation Toposequence in the Gatineau River Valley, Quebec
Forests 2016, 7(11), 254; doi:10.3390/f7110254
Received: 26 August 2016 / Revised: 12 October 2016 / Accepted: 23 October 2016 / Published: 28 October 2016
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Abstract
This study measured changes in forest composition that have occurred since the preindustrial era along the toposequence of the Gatineau River Valley, Quebec, Canada (5650 km2), based on survey records prior to colonization (1804–1864) and recent forest inventories (1982–2006). Changes in
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This study measured changes in forest composition that have occurred since the preindustrial era along the toposequence of the Gatineau River Valley, Quebec, Canada (5650 km2), based on survey records prior to colonization (1804–1864) and recent forest inventories (1982–2006). Changes in forest cover composition over time were found to be specific to toposequence position. Maple and red oak are now more frequent on upper toposequence positions (+26%, +21%, respectively), whereas yellow birch, eastern hemlock, and American beech declined markedly (−34% to −17%). Poplar is more frequent throughout the landscape, but particularly on mid-toposequence positions (+40%). In contrast, white pine, frequent on all toposequence positions in the preindustrial forest, is now confined to shallow and coarse-textured soils (−20%). The preindustrial forest types of the study area were mostly dominated by maple, yellow birch, and beech, with strong components of white pine, hemlock, and eastern white cedar, either as dominant or codominant species. In a context of ongoing anthropogenic disturbances and environmental changes, it is probably not possible to restore many of these types, except where targeted silvicultural interventions could increase the presence of certain species. The new forest types observed should be managed to ensure continuity of vital ecosystem services and functions as disturbance regimes evolve. Full article
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Open AccessArticle Enhancing Forest Growth and Yield Predictions with Airborne Laser Scanning Data: Increasing Spatial Detail and Optimizing Yield Curve Selection through Template Matching
Forests 2016, 7(11), 255; doi:10.3390/f7110255
Received: 13 July 2016 / Revised: 15 October 2016 / Accepted: 22 October 2016 / Published: 28 October 2016
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Abstract
Accurate information on both the current stock and future growth and yield of forest resources is critical for sustainable forest management. We demonstrate a novel approach to utilizing airborne laser scanning (ALS)-derived forest stand attributes to determine future growth and yield of six
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Accurate information on both the current stock and future growth and yield of forest resources is critical for sustainable forest management. We demonstrate a novel approach to utilizing airborne laser scanning (ALS)-derived forest stand attributes to determine future growth and yield of six attributes at a sub-stand (25 m grid cell) level of detail: dominant height (HMAX), Lorey’s height (HL), quadratic mean diameter (QMD), basal area (BA), whole stem volume (V), and trees per hectare (TPH). The approach is designed to find the most appropriate matching yield curve and project the attributes to the age of 80 years. Comparisons to conventional plot-level projections resulted in relative mean differences of 13.4% (HMAX), −27.1% (HL), 18.8% (QMD), 12.0% (BA), 18.6% (V), and −17.5% (TPH). The respective relative root mean squared difference values were: 31.1%, 38.4%, 19.8%, 19.8%, 21.8%, and 38.4%. Differences were driven mostly by stand-level age and site index. The uncertainty of cell-level yield curve assignment was used to refine stand-level summaries. The novel contribution of this study is in the application of growth and yield models at the cell level, combined with the use of ALS-derived attributes to optimize yield curve selection via template matching. Full article
(This article belongs to the Special Issue LiDAR Remote Sensing of Forest Resources)
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Open AccessArticle Seasonal Variation in Soil Greenhouse Gas Emissions at Three Age-Stages of Dawn Redwood (Metasequoia glyptostroboides) Stands in an Alluvial Island, Eastern China
Forests 2016, 7(11), 256; doi:10.3390/f7110256
Received: 26 August 2016 / Revised: 18 October 2016 / Accepted: 21 October 2016 / Published: 4 November 2016
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Abstract
Greenhouse gas (GHG) emissions are an important part of the carbon (C) and nitrogen (N) cycle in forest soil. However, soil greenhouse gas emissions in dawn redwood (Metasequoia glyptostroboides) stands of different ages are poorly understood. To elucidate the effect of
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Greenhouse gas (GHG) emissions are an important part of the carbon (C) and nitrogen (N) cycle in forest soil. However, soil greenhouse gas emissions in dawn redwood (Metasequoia glyptostroboides) stands of different ages are poorly understood. To elucidate the effect of plantation age and environmental factors on soil GHG emissions, we used static chamber/gas chromatography (GC) system to measure soil GHG emissions in an alluvial island in eastern China for two consecutive years. The soil was a source of CO2 and N2O and a sink of CH4 with annual emissions of 5.5–7.1 Mg C ha−1 year−1, 0.15–0.36 kg N ha−1 year−1, and 1.7–4.5 kg C ha−1 year−1, respectively. A clear exponential correlation was found between soil temperature and CO2 emission, but a negative linear correlation was found between soil water content and CO2 emission. Soil temperature had a significantly positive effect on CH4 uptake and N2O emission, whereas no significant correlation was found between CH4 uptake and soil water content, and N2O emission and soil water content. These results implied that older forest stands might cause more GHG emissions from the soil into the atmosphere because of higher litter/root biomass and soil carbon/nitrogen content compared with younger stands. Full article
(This article belongs to the Special Issue Forest Soil Respiration under Climate Changing)
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Open AccessArticle Effects of Boreal Timber Rafting on the Composition of Arctic Driftwood
Forests 2016, 7(11), 257; doi:10.3390/f7110257
Received: 16 August 2016 / Revised: 22 October 2016 / Accepted: 26 October 2016 / Published: 31 October 2016
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Abstract
Wood from the boreal forest represents an important resource for paper production and sawmill processing. Due to poor infrastructure and high transportation costs on land, timbers are often transported over long distances along large river systems. Industrial river rafting activities started at the
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Wood from the boreal forest represents an important resource for paper production and sawmill processing. Due to poor infrastructure and high transportation costs on land, timbers are often transported over long distances along large river systems. Industrial river rafting activities started at the end of the 19th century and were intensified in western Russia and central Siberia from the 1920s to the 1980s. After initial single stem rafting, timber is today mostly floated in ship-guided rafts. Lost wood can be transported further to the Arctic Ocean, where it may drift within sea ice over several years and thousands of kilometers before being deposited along (sub-)Arctic coastlines. Here, we introduce dendro-dated tree-ring width series of 383 driftwood samples from logged timber that were collected along different driftwood-recipient coastlines in Greenland, Iceland and Svalbard. The majority of driftwood is Pinus sylvestris from the southern Yenisei region in central Siberia, whereas Larix sp. and Picea sp. from western Russia and eastern Siberia are rare. Although our results are based on a small sample collection, they clearly show the importance of timber rafting on species, age and origin of Arctic driftwood and indicate the immense loss of material during wood industrial river floating. Full article
(This article belongs to the Special Issue Dynamics and Management of Boreal Forests)
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Open AccessArticle Distribution of Natural and Planted Forests in the Yanhe River Catchment: Have We Planted Trees on the Right Sites?
Forests 2016, 7(11), 258; doi:10.3390/f7110258
Received: 29 July 2016 / Revised: 15 October 2016 / Accepted: 25 October 2016 / Published: 31 October 2016
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Abstract
Planting trees on the right sites is the first principle in silviculture, but it is not easy to apply at a large scale, especially in complex terrain such as mountainous regions. In hilly and gully landscapes of China’s Loess Plateau, the environmental heterogeneity
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Planting trees on the right sites is the first principle in silviculture, but it is not easy to apply at a large scale, especially in complex terrain such as mountainous regions. In hilly and gully landscapes of China’s Loess Plateau, the environmental heterogeneity is so great that it is very difficult to choose the right sites for planting trees. The long history of vegetation destruction makes it difficult to have a reference for restoration programs. In this paper, we compared the distribution of actual forest to an existing potential natural vegetation (PNV) map to see the mismatch with the sites. The differences in environmental conditions between natural forest and mismatched planted forest were investigated. The results showed that significant differences existed in the environmental conditions between them. The mean rainfall and temperature for natural forest were 512.20 ± 11.42 mm and 8.23 ± 0.55 °C, respectively, but 497.96 ± 14.92 mm and 8.72 ± 0.97 °C, respectively, for the mismatched planted forest. Evaporation was not only different in range (816–953 mm vs. 816–1023 mm), but also significantly different in mean values (888.31 ± 14.35 mm natural forest vs. 895.90 ± 30.55 mm planted forest). The slope gradient of natural forest and mismatched planted forest was also significantly different (22.66° ± 8.82° vs. 24.24° ± 9.86°). The results identified that 58% of the existing forest in the Yanhe River catchment is planted forest that grows on steeper slopes, receives lower rainfall, has higher temperatures and higher evaporation. The average soil water content for sites with planted forest was found to be 5.98% ± 0.32% compared to 7.52% ± 0.33% for natural forest. We conclude that the main cause of dwarfed, slender, low productive and sparse planted forest in the Loess Plateau is planting trees at unsuitable sites. Our results highlight the importance of matching sites with the best potential vegetation types. Instead of using water harvesting techniques, we suggest that more focus should be placed on understanding environmental heterogeneity and its capacity to support particular vegetation types. This study is instructive for vegetation restoration planning and existing planted forest management in the future. Full article
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Open AccessArticle Estimation of Voxel-Based Above-Ground Biomass Using Airborne LiDAR Data in an Intact Tropical Rain Forest, Brunei
Forests 2016, 7(11), 259; doi:10.3390/f7110259
Received: 27 July 2016 / Revised: 23 October 2016 / Accepted: 25 October 2016 / Published: 31 October 2016
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Abstract
The advancement of LiDAR technology has enabled more detailed evaluations of forest structures. The so-called “Volumetric pixel (voxel)” has emerged as a new comprehensive approach. The purpose of this study was to estimate plot-level above-ground biomass (AGB) in different plot sizes of 20
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The advancement of LiDAR technology has enabled more detailed evaluations of forest structures. The so-called “Volumetric pixel (voxel)” has emerged as a new comprehensive approach. The purpose of this study was to estimate plot-level above-ground biomass (AGB) in different plot sizes of 20 m × 20 m and 30 m × 30 m, and to develop a regression model for AGB prediction. Both point cloud-based (PCB) and voxel-based (VB) metrics were used to maximize the efficiency of low-density LiDAR data within a dense forest. Multiple regression model AGB prediction performance was found to be greatest in the 30 m × 30 m plots, with R2, adjusted R2, and standard deviation values of 0.92, 0.87, and 35.13 Mg∙ha−1, respectively. Five out of the eight selected independent variables were derived from VB metrics and the other three were derived from PCB metrics. Validation of accuracy yielded RMSE and NRMSE values of 27.8 Mg∙ha−1 and 9.2%, respectively, which is a reasonable estimate for this structurally complex intact forest that has shown high NRMSE values in previous studies. This voxel-based approach enables a greater understanding of complex forest structure and is expected to contribute to the advancement of forest carbon quantification techniques. Full article
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Open AccessArticle Fire Regime Characteristics along Environmental Gradients in Spain
Forests 2016, 7(11), 262; doi:10.3390/f7110262
Received: 26 June 2016 / Revised: 28 October 2016 / Accepted: 1 November 2016 / Published: 4 November 2016
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Abstract
Concern regarding global change has increased the need to understand the relationship between fire regime characteristics and the environment. Pyrogeographical theory suggests that fire regimes are constrained by climate, vegetation and fire ignition processes, but it is not obvious how fire regime characteristics
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Concern regarding global change has increased the need to understand the relationship between fire regime characteristics and the environment. Pyrogeographical theory suggests that fire regimes are constrained by climate, vegetation and fire ignition processes, but it is not obvious how fire regime characteristics are related to those factors. We used a three-matrix approach with a multivariate statistical methodology that combined an ordination method and fourth-corner analysis for hypothesis testing to investigate the relationship between fire regime characteristics and environmental gradients across Spain. Our results suggest that fire regime characteristics (i.e., density and seasonality of fire activity) are constrained primarily by direct gradients based on climate, population, and resource gradients based on forest potential productivity. Our results can be used to establish a predictive model for how fire regimes emerge in order to support fire management, particularly as global environmental changes impact fire regime characteristics. Full article
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Open AccessArticle Mitigating the Stress of Drought on Soil Respiration by Selective Thinning: Contrasting Effects of Drought on Soil Respiration of Two Oak Species in a Mediterranean Forest
Forests 2016, 7(11), 263; doi:10.3390/f7110263
Received: 7 September 2016 / Revised: 25 October 2016 / Accepted: 28 October 2016 / Published: 4 November 2016
Cited by 1 | PDF Full-text (3239 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Drought has been shown to reduce soil respiration (SR) in previous studies. Meanwhile, studies of the effect of forest management on SR yielded contrasting results. However, little is known about the combined effect of drought and forest management on SR. To investigate if
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Drought has been shown to reduce soil respiration (SR) in previous studies. Meanwhile, studies of the effect of forest management on SR yielded contrasting results. However, little is known about the combined effect of drought and forest management on SR. To investigate if the drought stress on SR can be mitigated by thinning, we implemented plots of selective thinning and 15% reduced rainfall in a mixed forest consisting of the evergreen Quercus ilex and deciduous Quercus cerrioides; we measured SR seasonally from 2004 to 2007. Our results showed a clear soil moisture threshold of 9%; above this value, SR was strongly dependent on soil temperature, with Q10 of 3.0–3.8. Below this threshold, the relationship between SR and soil temperature weakened. We observed contrasting responses of SR of target oak species to drought and thinning. Reduced rainfall had a strong negative impact on SR of Q. cerrioides, whereas the effect on SR for Q. ilex was marginal or even positive. Meanwhile, selective thinning increased SR of Q. cerrioides, but reduced that of Q. ilex. Overall, our results showed that the negative effect of drought on SR can be offset through selective thinning, but the effect is attenuated with time. Full article
(This article belongs to the Special Issue Forest Soil Respiration under Climate Changing)
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Open AccessArticle Effects of Hurricane-Felled Tree Trunks on Soil Carbon, Nitrogen, Microbial Biomass, and Root Length in a Wet Tropical Forest
Forests 2016, 7(11), 264; doi:10.3390/f7110264
Received: 29 August 2016 / Revised: 24 October 2016 / Accepted: 31 October 2016 / Published: 4 November 2016
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Abstract
Decaying coarse woody debris can affect the underlying soil either by augmenting nutrients that can be exploited by tree roots, or by diminishing nutrient availability through stimulation of microbial nutrient immobilization. We analyzed C, N, microbial biomass C and root length in closely
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Decaying coarse woody debris can affect the underlying soil either by augmenting nutrients that can be exploited by tree roots, or by diminishing nutrient availability through stimulation of microbial nutrient immobilization. We analyzed C, N, microbial biomass C and root length in closely paired soil samples taken under versus 20–50 cm away from large trunks of two species felled by Hugo (1989) and Georges (1998) three times during wet and dry seasons over the two years following the study conducted by Georges. Soil microbial biomass, % C and % N were significantly higher under than away from logs felled by both hurricanes (i.e., 1989 and 1998), at all sampling times and at both depths (0–10 and 10–20 cm). Frass from wood boring beetles may contribute to early effects. Root length was greater away from logs during the dry season, and under logs in the wet season. Root length was correlated with microbial biomass C, soil N and soil moisture (R = 0.36, 0.18, and 0.27, respectively; all p values < 0.05). Microbial biomass C varied significantly among seasons but differences between positions (under vs. away) were only suggestive. Microbial C was correlated with soil N (R = 0.35). Surface soil on the upslope side of the logs had significantly more N and microbial biomass, likely from accumulation of leaf litter above the logs on steep slopes. We conclude that decaying wood can provide ephemeral resources that are exploited by tree roots during some seasons. Full article
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Open AccessArticle Effects of Lakes on Wildfire Activity in the Boreal Forests of Saskatchewan, Canada
Forests 2016, 7(11), 265; doi:10.3390/f7110265
Received: 21 August 2016 / Revised: 28 October 2016 / Accepted: 31 October 2016 / Published: 5 November 2016
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Abstract
Large lakes can act as firebreaks resulting in distinct patterns in the forest mosaic. Although this is well acknowledged, much less is known about how wildfire is affected by different landscape measures of water and their interactions. Here we examine how these factors
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Large lakes can act as firebreaks resulting in distinct patterns in the forest mosaic. Although this is well acknowledged, much less is known about how wildfire is affected by different landscape measures of water and their interactions. Here we examine how these factors relate to historic patterns of wildfire over a 35-year period (1980–2014) for the boreal forest of Saskatchewan, Canada. This includes the amount of water in different-sized neighborhoods, the presence of islands, and the direction, distance, and shape of nearest lake of different sizes. All individual factors affected wildfire presence, with lake sizes ≥5000 ha and amount of water within a 1000-ha surrounding area the most supported spatial scales. Overall, wildfires were two-times less likely on islands, more likely further from lakes that were circular in shape, and in areas with less surrounding water. Interactive effects were common, including the effect of direction to lake as a function of distance from lakeshore and amount of surrounding water. Our results point to a strong, but complex, bottom-up control of local wildfire activity based on the configuration of natural firebreaks. In fact, fire rotation periods predicted for one area varied more than 15-fold (<47 to >700 years) depending on local patterns in lakes. Old-growth forests within this fire-prone ecosystem are therefore likely to depend on the surrounding configuration of larger lakes. Full article
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Open AccessArticle Growth Characteristics of Ectomycorrhizal Seedlings of Quercus glauca, Quercus salicina, Quercus myrsinaefolia, and Castanopsis cuspidata Planted in Calcareous Soil
Forests 2016, 7(11), 266; doi:10.3390/f7110266
Received: 29 August 2016 / Revised: 17 October 2016 / Accepted: 31 October 2016 / Published: 5 November 2016
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Abstract
To verify the acclimation capacity of evergreen Fagaceae species on calcareous soil, we compared ecophysiological traits between Quercus glauca Thunb., Q. salicina Blume, Q. myrsinaefolia Blume, and Castanopsis cuspidata (Thunb.) Schottky as typical woody species from southwestern Japan. We also examined the inoculation
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To verify the acclimation capacity of evergreen Fagaceae species on calcareous soil, we compared ecophysiological traits between Quercus glauca Thunb., Q. salicina Blume, Q. myrsinaefolia Blume, and Castanopsis cuspidata (Thunb.) Schottky as typical woody species from southwestern Japan. We also examined the inoculation effects of the ectomycorrhizal (ECM) fungi Astraeus hygrometricus and Scleroderma citrinum, and planted seedlings in calcareous soil collected from a limestone quarry. We measured growth, ectomycorrhizal colonization, photosynthetic rate, and concentrations of nutrients in plant organs for A. hygrometricus-inoculated, S. citrinum-inoculated, and non-ECM seedlings. Six months after planting on calcareous soil, seedlings of the three Quercus species inoculated with A. hygrometricus were larger than non-ECM seedlings, especially Q. salicina, which showed the greatest increase in dry mass. The dry mass of C. cuspidata seedlings was inferior to that of the three Quercus species. In the nutrient-uptake analysis, phosphorus, manganese, and iron uptakes were suppressed in calcareous soil for each Fagaceae species. However, seedlings of Fagaceae species that showed better growth had increased concentrations of phosphorus in roots. We concluded that seedlings of Q. salicina and Q. glauca inoculated with A. hygrometricus were best suited to calcareous soil and were considered as useful species for the reforestation in limestone quarries. Full article
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Open AccessArticle Spatial Distribution of Soil Nitrogen, Phosphorus and Potassium Stocks in Moso Bamboo Forests in Subtropical China
Forests 2016, 7(11), 267; doi:10.3390/f7110267
Received: 15 August 2016 / Revised: 24 October 2016 / Accepted: 31 October 2016 / Published: 7 November 2016
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Abstract
Moso bamboo is famous for fast growth and biomass accumulation, as well as high annual output for timber and bamboo shoots. These high outputs require high nutrient inputs to maintain and improve stand productivity. Soil nitrogen (N), phosphorus (P), and potassium (K) are
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Moso bamboo is famous for fast growth and biomass accumulation, as well as high annual output for timber and bamboo shoots. These high outputs require high nutrient inputs to maintain and improve stand productivity. Soil nitrogen (N), phosphorus (P), and potassium (K) are important macronutrients for plant growth and productivity. Due to high variability of soils, analysing spatial patterns of soil N, P, and K stocks is necessary for scientific nutrient management of Moso bamboo forests. In this study, soils were sampled from 138 locations across Yong’an City and ordinary kriging was applied for spatial interpolation of soil N, P, and K stocks within 0–60 cm. The nugget-to-sill ratio suggested a strong spatial dependence for soil N stock and a moderate spatial dependence for soil P and K stocks, indicating that soil N stock was mainly controlled by intrinsic factors while soil P and K stocks were controlled by both intrinsic and extrinsic factors. Different spatial patterns were observed for soil N, P, and K stocks across the study area, indicating that fertilizations with different ratios of N:P:K should be applied for different sites to maintain and improve stand productivity. The total soil N, P, and K stocks within 0–60 cm were 0.624, 0.020, and 0.583 Tg, respectively, indicating soils were important pools for N, P, and K. Full article
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Open AccessArticle Developing and Implementing Climate Change Adaptation Options in Forest Ecosystems: A Case Study in Southwestern Oregon, USA
Forests 2016, 7(11), 268; doi:10.3390/f7110268
Received: 1 September 2016 / Revised: 24 October 2016 / Accepted: 2 November 2016 / Published: 7 November 2016
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Abstract
Climate change will likely have significant effects on forest ecosystems worldwide. In Mediterranean regions, such as that in southwestern Oregon, USA, changes will likely be driven mainly by wildfire and drought. To minimize the negative effects of climate change, resource managers require tools
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Climate change will likely have significant effects on forest ecosystems worldwide. In Mediterranean regions, such as that in southwestern Oregon, USA, changes will likely be driven mainly by wildfire and drought. To minimize the negative effects of climate change, resource managers require tools and information to assess climate change vulnerabilities and to develop and implement adaptation actions. We developed an approach to facilitate development and implementation of climate change adaptation options in forest management. This approach, applied in a southwestern Oregon study region, involved establishment of a science–manager partnership, a science-based assessment of forest and woodland vulnerabilities to climate change, climate change education in multiple formats, hands-on development of adaptation options, and application of tools to incorporate climate change in planned projects. Through this approach, we improved local manager understanding of the potential effects of climate change in southwestern Oregon, and enabled evaluation of proposed management activities in the context of climatic stressors. Engaging managers throughout the project increased ownership of the process and outcomes, as well as the applicability of the adaptation options to on-the-ground actions. Science–management partnerships can effectively incorporate evolving science, regardless of the socio-political environment, and facilitate timely progress in adaptation to climate change. Full article
(This article belongs to the Special Issue Climate Change Impacts on the Dynamics of Forest Ecosystems)
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Open AccessArticle Soil and Stocking Effects on Caliciopsis Canker of Pinus strobus L.
Forests 2016, 7(11), 269; doi:10.3390/f7110269
Received: 6 September 2016 / Revised: 26 October 2016 / Accepted: 4 November 2016 / Published: 11 November 2016
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Abstract
Soil and stand density were found to be promising predictive variables associated with damage by the emerging disease of eastern white pine, Caliciopsis canker, in a 2014 survey with randomly selected eastern white pine (Pinus strobus L.) stands. The objective of this
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Soil and stand density were found to be promising predictive variables associated with damage by the emerging disease of eastern white pine, Caliciopsis canker, in a 2014 survey with randomly selected eastern white pine (Pinus strobus L.) stands. The objective of this study was to further investigate the relationship between soil and stocking in eastern white pine forests of New England by stratifying sampling across soils and measuring stand density more systematically. A total of 62 eastern white pine stands were sampled during 2015–2016. Stands were stratified across soil groups and several prism plots were established at each site to measure stand density and determine stocking. Caliciopsis canker incidence in mature trees was greater in sites with drier or shallow soils compared to sites with loamy soils and in adequately stocked stands compared to understocked stands (p < 0.0001). Caliciopsis canker signs and symptoms were observed in all size classes. Live crown ratio, a measure of forest health, decreased with increasing Caliciopsis canker symptom severity. The fungal pathogen, Caliciopsis pinea Peck, was successfully isolated from cankers on trees growing in each soil group. Forest managers will need to consider damage caused by Caliciopsis canker related to stand factors such as soil and stocking when regenerating white pine stands. Full article
(This article belongs to the Special Issue Forest Pathology and Plant Health)
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Open AccessArticle Understanding the Fate of Applied Nitrogen in Pine Plantations of the Southeastern United States Using 15N Enriched Fertilizers
Forests 2016, 7(11), 270; doi:10.3390/f7110270
Received: 29 August 2016 / Revised: 2 November 2016 / Accepted: 5 November 2016 / Published: 11 November 2016
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Abstract
This study was conducted to determine the efficacy of using enhanced efficiency fertilizer (EEFs) products compared to urea to improve fertilizer nitrogen use efficiency (FNUE) in forest plantations. All fertilizer treatments were labeled with 15N (0.5 atom percent) and applied to 100
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This study was conducted to determine the efficacy of using enhanced efficiency fertilizer (EEFs) products compared to urea to improve fertilizer nitrogen use efficiency (FNUE) in forest plantations. All fertilizer treatments were labeled with 15N (0.5 atom percent) and applied to 100 m2 circular plots at 12 loblolly pine stands (Pinus taeda L.) across the southeastern United States. Total fertilizer N recovery for fertilizer treatments was determined by sampling all primary ecosystem components and using a mass balance calculation. Significantly more fertilizer N was recovered for all EEFs compared to urea, but there were generally no differences among EEFs. The total fertilizer N ecosystem recovery ranged from 81.9% to 84.2% for EEFs compared to 65.2% for urea. The largest amount of fertilizer N recovered for all treatments was in the loblolly pine trees (EEFs: 38.5%–49.9%, urea: 34.8%) and soil (EEFs: 30.6%–38.8%, urea: 28.4%). This research indicates that a greater ecosystem fertilizer N recovery for EEFs compared to urea in southeastern pine plantations can potentially lead to increased FNUE in these systems. Full article
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Open AccessArticle Modeling the Boundaries of Plant Ecotones of Mountain Ecosystems
Forests 2016, 7(11), 271; doi:10.3390/f7110271
Received: 30 August 2016 / Revised: 28 October 2016 / Accepted: 5 November 2016 / Published: 12 November 2016
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Abstract
The ecological second-order phase transition model has been used to describe height-dependent changes in the species composition of mountain forest ecosystems. Forest inventory data on the distribution of various tree species in the Sayan Mountains (south Middle Siberia) are in good agreement with
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The ecological second-order phase transition model has been used to describe height-dependent changes in the species composition of mountain forest ecosystems. Forest inventory data on the distribution of various tree species in the Sayan Mountains (south Middle Siberia) are in good agreement with the model proposed in this study. The model was used to estimate critical heights for different altitudinal belts of vegetation, determine the boundaries and extents of ecotones between different vegetation belts, and reveal differences in the ecotone boundaries between the north- and south-facing transects. An additional model is proposed to describe ecotone boundary shifts caused by climate change. Full article
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Open AccessArticle Optimization Forest Thinning Measures for Carbon Budget in a Mixed Pine-Oak Stand of the Qingling Mountains, China: A Case Study
Forests 2016, 7(11), 272; doi:10.3390/f7110272
Received: 18 September 2016 / Revised: 1 November 2016 / Accepted: 3 November 2016 / Published: 12 November 2016
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Abstract
Forest thinning is a silviculture treatment for sustainable forest management. It may promote growth of the remaining individuals by decreasing stand density, reducing competition, and increasing light and nutrient availability to increase carbon sequestration in the forest ecosystem. However, the action also increases
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Forest thinning is a silviculture treatment for sustainable forest management. It may promote growth of the remaining individuals by decreasing stand density, reducing competition, and increasing light and nutrient availability to increase carbon sequestration in the forest ecosystem. However, the action also increases carbon loss simultaneously by reducing carbon and other nutrient inputs as well as exacerbating soil CO2 efflux. To achieve a maximum forest carbon budget, the central composite design with two independent variables (thinning intensity and thinning residual removal rate) was explored in a natural pine-oak mixed stand in the Qinling Mountains, China. The net primary productivity of living trees was estimated and soil CO2 efflux was stimulated by the Yasso07 model. Based on two years observation, the preliminary results indicated the following. Evidently chemical compounds of the litter of the tree species affected soil CO2 efflux stimulation. The thinning residual removal rate had a larger effect than thinning intensity on the net ecosystem productivity. When the selective thinning intensity and residual removal rate was 12.59% and 66.62% concurrently, the net ecosystem productivity reached its maximum 53.93 t·ha−1·year−1. The lower thinning intensity and higher thinning residual removal rated benefited the net ecosystem productivity. Full article
(This article belongs to the Special Issue Forest Soil Respiration under Climate Changing)
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Open AccessArticle Fire Scenarios in Spain: A Territorial Approach to Proactive Fire Management in the Context of Global Change
Forests 2016, 7(11), 273; doi:10.3390/f7110273
Received: 8 September 2016 / Revised: 22 October 2016 / Accepted: 8 November 2016 / Published: 12 November 2016
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Abstract
Humans and fire form a coupled and co-evolving natural-human system in Mediterranean-climate ecosystems. In this context, recent trends in landscape change, such as urban sprawl or the abandoning of agricultural and forest land management in line with new models of economic development and
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Humans and fire form a coupled and co-evolving natural-human system in Mediterranean-climate ecosystems. In this context, recent trends in landscape change, such as urban sprawl or the abandoning of agricultural and forest land management in line with new models of economic development and lifestyles, are leading to new fire scenarios. A fire scenario refers to the contextual factors of a fire regime, i.e., the environmental, socio-economic and policy drivers of wildfire initiation and propagation on different spatial and temporal scales. This is basically a landscape concept linking territorial dynamics (related to ecosystem evolution and settlement patterns) with a fire regime (ignition causes; spread patterns; fire frequency, severity, extent and seasonality). The aim of this article is to identify and characterize these land-based fire scenarios in Spain on a national and regional scale, using a GIS-based methodology to perform a spatial analysis of the area attributes of homogenous fire spread patterns. To do this, the main variables considered are: land use/land cover, fuel load and recent fire history. The final objective is to reduce territorial vulnerability to forest wildfires and facilitate the adaptation of fire policies and land management systems to current challenges of preparedness and uncertainty management. Full article
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Open AccessArticle Haploids in Conifer Species: Characterization and Chromosomal Integrity of a Maritime Pine Cell Line
Forests 2016, 7(11), 274; doi:10.3390/f7110274
Received: 4 September 2016 / Revised: 4 November 2016 / Accepted: 9 November 2016 / Published: 12 November 2016
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Abstract
Haploids are a valuable tool for genomic studies in higher plants, especially those with huge genome size and long juvenile periods, such as conifers. In these species, megagametophyte cultures have been widely used to obtain haploid callus and somatic embryogenic lines. One of
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Haploids are a valuable tool for genomic studies in higher plants, especially those with huge genome size and long juvenile periods, such as conifers. In these species, megagametophyte cultures have been widely used to obtain haploid callus and somatic embryogenic lines. One of the main problems associated with tissue culture is the potential genetic instability of the regenerants. Because of this, chromosomal stability of the callus and/or somatic embryos should also be assessed. To this end, chromosome counting, flow cytometry and genotyping using microsatellites have been reported. Here, we present an overview of the work done in conifers, with special emphasis on the production of a haploid cell line in maritime pine (Pinus pinaster L.) and the use of a set of molecular markers, which includes Single Nucleotide Polymorphisms (SNPs) and microsatellites or Single Sequence Repeats (SSRs), to validate chromosomal integrity confirming the presence of all chromosomic arms. Full article
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Open AccessArticle Wood or Laminate?—Psychological Research of Customer Expectations
Forests 2016, 7(11), 275; doi:10.3390/f7110275
Received: 23 September 2016 / Revised: 25 October 2016 / Accepted: 8 November 2016 / Published: 12 November 2016
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Abstract
Wood is generally associated with being practical, aesthetic and economy-friendly. Using wood in interior settings also can be based on psychological expectations and assumptions, as wood is attributed as warmer, more homely, more relaxing and more inviting. However, when investigating psychological differences, wood
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Wood is generally associated with being practical, aesthetic and economy-friendly. Using wood in interior settings also can be based on psychological expectations and assumptions, as wood is attributed as warmer, more homely, more relaxing and more inviting. However, when investigating psychological differences, wood is usually compared to carpets, glass, leather, stone, or plastic but is not compared to a visually similar material such as laminate. The aim of this study is to analyze and compare the various psychological characteristics related to wooden and laminate materials in interior settings. The experimental design was a 2 × 2 design (material, sequence) with repeated measures for material. Forty participants were asked to evaluate a framed piece of wood floor and a framed piece of laminate floor regarding technical, practical, and psychological aspects. Further, three questions about one’s purchase decision were asked. The results show that the wooden floor was evaluated significantly better than the laminate floor regarding “materials and processing”, “atmosphere”, and “values and symbolic functions”. For the criterion “health”, a tendency in favor of wood could be found. In addition, the participants would more likely recommend and purchase wooden products and also accept more deficiencies in wooden products. Full article
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Open AccessArticle Effect of Tree Spacing on Tree Level Volume Growth, Morphology, and Wood Properties in a 25-Year-Old Pinus banksiana Plantation in the Boreal Forest of Quebec
Forests 2016, 7(11), 276; doi:10.3390/f7110276
Received: 30 August 2016 / Revised: 2 November 2016 / Accepted: 8 November 2016 / Published: 12 November 2016
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Abstract
The number of planted trees per hectare influences individual volume growth, which in turn can affect wood properties. The objective of this study was to assess the effect of six different plantation spacings of jack pine (Pinus banksiana Lamb.) 25 years following
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The number of planted trees per hectare influences individual volume growth, which in turn can affect wood properties. The objective of this study was to assess the effect of six different plantation spacings of jack pine (Pinus banksiana Lamb.) 25 years following planting on tree growth, morphology, and wood properties. Stem analyses were performed to calculate annual and cumulative diameter, height, and volume growth. For morphological and wood property measurements several parameters were analyzed: diameter of the largest branch, live crown ratio, wood density, and the moduli of elasticity and rupture on small clear samples. The highest volume growth for individual trees was obtained in the 1111 trees/ha plantation, while the lowest was in the 4444 trees/ha plantation. Wood density and the moduli of elasticity and rupture did not change significantly between the six plantation spacings, but the largest branch diameter was significantly higher in the 1111 trees/ha (3.26 cm mean diameter) compared with the 4444 trees/ha spacing (2.03 cm mean diameter). Based on this study, a wide range of spacing induced little negative effect on the measured wood properties, except for the size of knots. Increasing the initial spacing of jack pine plantations appears to be a good choice if producing large, fast-growing stems is the primary goal, but lumber mechanical and visual properties could be decreased due to the larger branch diameter. Full article
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Open AccessArticle Resource Utilization by Native and Invasive Earthworms and Their Effects on Soil Carbon and Nitrogen Dynamics in Puerto Rican Soils
Forests 2016, 7(11), 277; doi:10.3390/f7110277
Received: 22 September 2016 / Revised: 5 November 2016 / Accepted: 6 November 2016 / Published: 15 November 2016
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Abstract
Resource utilization by earthworms affects soil C and N dynamics and further colonization of invasive earthworms. By applying 13C-labeled Tabebuia heterophylla leaves and 15N-labeled Andropogon glomeratus grass, we investigated resource utilization by three earthworm species (invasive endogeic Pontoscolex corethrurus, native
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Resource utilization by earthworms affects soil C and N dynamics and further colonization of invasive earthworms. By applying 13C-labeled Tabebuia heterophylla leaves and 15N-labeled Andropogon glomeratus grass, we investigated resource utilization by three earthworm species (invasive endogeic Pontoscolex corethrurus, native anecic Estherella sp, and native endogeic Onychochaeta borincana) and their effects on soil C and N dynamics in Puerto Rican soils in a 22-day laboratory experiment. Changes of 13C/C and 15N/N in soils, earthworms, and microbial populations were analyzed to evaluate resource utilization by earthworms and their influences on C and N dynamics. Estherella spp. utilized the 13C-labeled litter; however, its utilization on the 13C-labeled litter reduced when cultivated with P. corethrurus and O. borincana. Both P. corethrurus and O. borincana utilized the 13C-labeled litter and 15C-labeled grass roots and root exudates. Pontoscolex corethrurus facilitated soil respiration by stimulating 13C-labeled microbial activity; however, this effect was suppressed possibly due to the changes in the microbial activities or community when coexisting with O. borincana. Increased soil N mineralization by individual Estherella spp. and O. borincana was reduced in the mixed-species treatments. The rapid population growth of P. corethrurus may increase competition pressure on food resources on the local earthworm community. The relevance of resource availability to the population growth of P. corethrurus and its significance as an invasive species is a topic in need of future research. Full article
Open AccessArticle Recent Afforestation in the Iowa River and Vorskla River Basins: A Comparative Trends Analysis
Forests 2016, 7(11), 278; doi:10.3390/f7110278
Received: 6 September 2016 / Revised: 18 October 2016 / Accepted: 5 November 2016 / Published: 15 November 2016
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Abstract
Afforestation trends were compared between two continentally-distinct, yet similar ecoregions to characterize similarities or differences in forest advancement due to natural and anthropogenic forcings. Temporal changes in forest cover were analyzed using high resolution aerial and satellite photographs for Southeast Iowa, USA, and
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Afforestation trends were compared between two continentally-distinct, yet similar ecoregions to characterize similarities or differences in forest advancement due to natural and anthropogenic forcings. Temporal changes in forest cover were analyzed using high resolution aerial and satellite photographs for Southeast Iowa, USA, and satellite photographs for the western Belgorod Oblast, Russia. An increase in forested area was shown to occur over a 44-year period from 1970–2014 in Iowa where afforestation was reflected by the aggregation of smaller forest units. In the Belgorod region the opposite occurred in that there was an increase in the number of smaller forested units. The rate of forest expansion into open grassland areas, previously used as haying lands and pastures, was 14 m decade−1 and 8 m decade−1 in Iowa and the Belgorod Oblast, respectively. Based on current trends, predicted times for complete forest coverage in the study areas was estimated to be 80 years in Iowa and 300 years in the Belgorod Oblast. In both the Iowa and Belgorod Oblast, there was an increase in annual precipitation at the end of the 20th and the beginning of the 21st centuries, thus providing a contributing mechanism to forest advancement in the study regions and implications for future management practices. Full article
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Open AccessArticle Surface CO2 Exchange Dynamics across a Climatic Gradient in McKenzie Valley: Effect of Landforms, Climate and Permafrost
Forests 2016, 7(11), 279; doi:10.3390/f7110279
Received: 26 July 2016 / Revised: 3 November 2016 / Accepted: 5 November 2016 / Published: 15 November 2016
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Abstract
Northern regions are experiencing considerable climate change affecting the state of permafrost, peat accumulation rates, and the large pool of carbon (C) stored in soil, thereby emphasizing the importance of monitoring surface C fluxes in different landform sites along a climate gradient. We
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Northern regions are experiencing considerable climate change affecting the state of permafrost, peat accumulation rates, and the large pool of carbon (C) stored in soil, thereby emphasizing the importance of monitoring surface C fluxes in different landform sites along a climate gradient. We studied surface net C exchange (NCE) and ecosystem respiration (ER) across different landforms (upland, peat plateau, collapse scar) in mid-boreal to high subarctic ecoregions in the Mackenzie Valley of northwestern Canada for three years. NCE and ER were measured using automatic CO2 chambers (ADC, Bioscientific LTD., Herts, England), and soil respiration (SR) was measured with solid state infrared CO2 sensors (Carbocaps, Vaisala, Vantaa, Finland) using the concentration gradient technique. Both NCE and ER were primarily controlled by soil temperature in the upper horizons. In upland forest locations, ER varied from 583 to 214 g C·m−2·year−1 from mid-boreal to high subarctic zones, respectively. For the bog and peat plateau areas, ER was less than half that at the upland locations. Of SR, nearly 75% was generated in the upper 5 cm layer composed of live bryophytes and actively decomposing fibric material. Our results suggest that for the upland and bog locations, ER significantly exceeded NCE. Bryophyte NCE was greatest in continuously waterlogged collapsed areas and was negligible in other locations. Overall, upland forest sites were sources of CO2 (from 64 g·C·m−2·year−1 in the high subarctic to 588 g C·m−2·year−1 in mid-boreal zone); collapsed areas were sinks of C, especially in high subarctic (from 27 g·C·m−2 year−1 in mid-boreal to 86 g·C·m−2·year−1 in high subarctic) and peat plateaus were minor sources (from 153 g·C·m−2·year−1 in mid-boreal to 6 g·C·m−2·year−1 in high subarctic). The results are important in understanding how different landforms are responding to climate change and would be useful in modeling the effect of future climate change on the soil C balance in the northern regions. Full article
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Open AccessArticle Morphological Characteristics and Water-Use Efficiency of Siberian Elm Trees (Ulmus pumila L.) within Arid Regions of Northeast Asia
Forests 2016, 7(11), 280; doi:10.3390/f7110280
Received: 31 August 2016 / Revised: 31 October 2016 / Accepted: 8 November 2016 / Published: 17 November 2016
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Abstract
The Siberian elm (Ulmus pumila L.) is one of the most commonly found tree species in arid areas of northeast Asia. To understand the morphological and physiological characteristics of Siberian elms in arid regions, we analyzed leaves from seven study sites (five
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The Siberian elm (Ulmus pumila L.) is one of the most commonly found tree species in arid areas of northeast Asia. To understand the morphological and physiological characteristics of Siberian elms in arid regions, we analyzed leaves from seven study sites (five arid or semi-arid and two mesic) in China, Mongolia and the Republic of Korea, which covered a wide range of average annual precipitation (232 mm·year−1 to 1304 mm·year−1) under various aridity indexes (AI) and four different microenvironments: sand dune, steppe, riverside and forest. The traits of Siberian elms varied widely along different annual precipitation (P) and AI gradients. Tree height (H), leaf size (LS) and stomatal area per unit leaf area (AS/AL) decreased with increasing AI, whereas leaf mass per unit leaf area (LMA) and water-use efficiency (WUE) increased significantly. In addition, trees at the five arid sites showed significant differences in LS, LMA and AS/AL but not in H and WUE. Thus, our study indicated that indigenous Siberian elm trees in arid areas have substantially altered their morphological and physiological characteristics to avoid heat stress and increase water conservation in comparison to mesic areas. However, their changes differed depending on the surrounding microenvironment even in arid areas. Trees in sand dunes had a smaller LS, higher LMA, thicker leaf cuticle layer and higher stomatal density and AS than those in steppes and near a riverside. Full article
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Open AccessArticle Deforestation Effects on Soil Erosion in the Lake Kivu Basin, D.R. Congo-Rwanda
Forests 2016, 7(11), 281; doi:10.3390/f7110281
Received: 29 August 2016 / Revised: 4 November 2016 / Accepted: 9 November 2016 / Published: 17 November 2016
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Abstract
Deforestation and natural grassland conversion to agricultural land use constitute a major threat to soil and water conservation. This study aimed at assessing the status of land cover and land use (LCLU) in the Lake Kivu basin, and its related impacts in terms
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Deforestation and natural grassland conversion to agricultural land use constitute a major threat to soil and water conservation. This study aimed at assessing the status of land cover and land use (LCLU) in the Lake Kivu basin, and its related impacts in terms of soil erosion by water using the Universal Soil Erosion Equation (USLE) model. The results indicated that the Lake Kivu basin is exposed to soil erosion risk with a mean annual rate of 30 t·ha−1, and only 33% of the total non-water area is associated with a tolerable soil loss (≤10 t·ha−1·year−1). Due to both natural factors (abundant tropical precipitation and steep slopes) and anthropogenic activities without prior appropriate conservation practices, all land-use types—namely settlement, cropland, forestland, and grassland—are exposed to a severe mean erosion rate of 41 t·ha−1·year−1, 31 t·ha−1·year−1, 28 t·ha−1·year−1, and 20 t·ha−1·year−1, respectively. The cropland that occupied 74% of the non-water area in 2015 was the major contributor (75%) to the total annual soil loss in the Lake Kivu basin. This study showed that conservation practices in the cropland cells would result in a mean erosion rate of 7 t·ha−1·year−1, 18 t·ha−1·year−1, and 35 t·ha−1·year−1 for terracing, strip-cropping, and contouring, respectively. The adoption of terracing would be the best conservation practice, among others, that could reduce soil erosion in cropland areas up to about 23%. The erosion risk minimization in forests and grasslands implies an increase in overstorey canopy and understorey vegetation, and control of human activities such as fires, mining, soil compaction from domestic animals grazing, and so on. Soil erosion control in settled areas suggests, among other things, the revegetation of construction sites, establishment of outlet channels, rainfall water harvesting systems, and pervious paving block with grass. Full article
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Open AccessArticle Carbon and Nitrogen Pools and Fluxes in Adjacent Mature Norway Spruce and European Beech Forests
Forests 2016, 7(11), 282; doi:10.3390/f7110282
Received: 19 September 2016 / Revised: 31 October 2016 / Accepted: 8 November 2016 / Published: 17 November 2016
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Abstract
We compared two adjacent mature forest ecosystem types (spruce vs. beech) to unravel the fate of assimilated carbon (C) and the cycling of organic and inorganic nitrogen (N) without the risk of the confounding influences of climatic and site differences when comparing different
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We compared two adjacent mature forest ecosystem types (spruce vs. beech) to unravel the fate of assimilated carbon (C) and the cycling of organic and inorganic nitrogen (N) without the risk of the confounding influences of climatic and site differences when comparing different sites. The stock of C in biomass was higher (258 t·ha−1) in the older (150 years) beech stand compared to the younger (80 years) planted spruce stand (192 t·ha−1), whereas N biomass pools were comparable (1450 kg·ha−1). Significantly higher C and N soil pools were measured in the beech stand, both in forest floor and mineral soil. Cumulative annual CO2 soil efflux was similar among stands, i.e., 9.87 t·ha−1·year−1 of C in the spruce stand and 9.01 t·ha−1·year−1 in the beech stand. Soil temperature explained 78% (Q10 = 3.7) and 72% (Q10 = 4.2) of variability in CO2 soil efflux in the spruce and beech stand, respectively. However, the rather tight N cycle in the spruce stand prevented inorganic N losses, whereas losses were higher in the beech stand and were dominated by nitrate in the mineral soil. Our results highlighted the long-term consequences of forest management on C and N cycling. Full article
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Open AccessCommunication Back to the Future: The Persistence of Horse Skidding in Large Scale Industrial Community Forests in Chihuahua, Mexico
Forests 2016, 7(11), 283; doi:10.3390/f7110283
Received: 12 August 2016 / Revised: 2 November 2016 / Accepted: 8 November 2016 / Published: 16 November 2016
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Abstract
Horse skidding for extracting logwood is characterized as a niche activity in small-scale forestry, limited to small tracts and low volumes, where environmental impacts and aesthetics are concerned, and to operations with no wood-processing facilities. This article documents and analyzes the widespread persistence,
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Horse skidding for extracting logwood is characterized as a niche activity in small-scale forestry, limited to small tracts and low volumes, where environmental impacts and aesthetics are concerned, and to operations with no wood-processing facilities. This article documents and analyzes the widespread persistence, current magnitude, and multiple advantages of horse skidding in large-scale industrial community forest enterprises in Chihuahua, Mexico. We extracted data from the logging permit files of 59 communities in the Sierra Tarahumara and conducted semi-structured interviews with community leaders and foresters in 18 communities, 17 random selections, and one purposefully selected case. There are nine communities that can be considered large-scale. Six of them use animal traction for 20%–100% of their volume. All have sawmills integrated with their operations. This includes the El Largo community with a ten-year volume of 3,169,019 m3 extracted from 123,810 ha entirely with horses. Respondents to the interviews report that horse skidding is more cost-effective than mechanized skidding, generates more employment, and has less impact on forests due to reduced carbon emissions. The widespread use of animal traction in large-scale industrial community forestry in Chihuahua demonstrates that horse skidding is not only a niche activity in small-scale forestry. Our data is preliminary, but we suggest that it highlights a need for further assessments of whether animal traction should be part of future efforts towards reduced impact, lower carbon emissions, and socially and economically just forest management. Full article
Open AccessArticle Spatial Pattern of the Mitochondrial and Chloroplast Genetic Variation in Poland as a Result of the Migration of Abies alba Mill. from Different Glacial Refugia
Forests 2016, 7(11), 284; doi:10.3390/f7110284
Received: 28 September 2016 / Revised: 2 November 2016 / Accepted: 9 November 2016 / Published: 17 November 2016
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Abstract
Currently, the information on the gene pool of silver fir (Abies alba Mill.) at the northeastern edge of its distribution in Poland is scarce and insufficient. Using the advantage provided by markers with different modes of inheritance, a hypothesis that gene flow
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Currently, the information on the gene pool of silver fir (Abies alba Mill.) at the northeastern edge of its distribution in Poland is scarce and insufficient. Using the advantage provided by markers with different modes of inheritance, a hypothesis that gene flow via both seeds and pollen contributed to the genetic structure across the entire analyzed region was investigated. The geographic distribution of maternally inherited mitochondrial DNA (mtDNA, nad5-4) and paternally inherited chloroplast DNA (cpDNA, psbC) variation was studied in 81 Polish populations and three reference populations from Ukraine and Romania. The spatial pattern of mtDNA haplotypes (dispersed via seeds) indicated that the Apennine Peninsula was the only maternal glacial refugium for the entire territory of Poland and also the Ukraine no 1 population, whereas the other two populations—Ukraine no 2 and Romania—had the haplotype representing the Balkan origin. By contrast, the cpDNA haplotypes (dispersed via pollen) from all studied Polish and reference populations showed that A. alba colonized the current natural range from two genetically distinct glacial refugia located on the Apennine and Balkan peninsulas. The occurrence of cpDNA haplotypes varied among the studied populations. Additionally, statistical analyses were used to infer the genetic structure of examined populations. Two distinct groups of A. alba populations were identified showing the postglacial geographic distribution of haplotypes of both mtDNA and cpDNA. A. alba is an important ecological and economic component of forest ecosystems in Europe. An understanding of the Holocene history of this species is relevant for planning sustainable forest management, and acquired data can contribute to strategies of conservation and restoration. Full article
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Open AccessArticle Assessment of Forest Management in Protected Areas Based on Multidisciplinary Research
Forests 2016, 7(11), 285; doi:10.3390/f7110285
Received: 6 September 2016 / Revised: 7 November 2016 / Accepted: 12 November 2016 / Published: 16 November 2016
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Abstract
The remnants of primeval Norway spruce forests in the European temperate zone are crucial for maintaining forest biodiversity in high mountain landscapes. This paper presents results of a multidisciplinary research and evaluation project on the management practices for mountain spruce forests in the
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The remnants of primeval Norway spruce forests in the European temperate zone are crucial for maintaining forest biodiversity in high mountain landscapes. This paper presents results of a multidisciplinary research and evaluation project on the management practices for mountain spruce forests in the Natura 2000 site (National Nature Reserve Serak-Keprnik in the Hruby Jesenik Mountains, the Czech Republic). Results are based on combining research on the historical development of the forest ecosystem and predictions of future dynamics using a forest growth simulation model. The presented results show that a non-intervention management strategy for mountain spruce forest in the next 50 years complies with the Natura 2000 requirement to maintain the existing character of the forest habitat. Thus, the results indicate that the current management plan for the spruce forests does not require significant corrections in the context of its conservation goals (i.e., maintaining biodiversity and current character of the forest ecosystem dominated by Norway spruce). The results of this study suggest that combining the knowledge of historical development with forest inventory data using forest growth simulation represents a suitable support tool for the assessment of management practices for forest habitats in protected areas. Full article
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Open AccessArticle Perceived Acceptability of Implementing Marker-Assisted Selection in the Forests of British Columbia
Forests 2016, 7(11), 286; doi:10.3390/f7110286
Received: 11 October 2016 / Revised: 7 November 2016 / Accepted: 12 November 2016 / Published: 18 November 2016
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Abstract
The forest sector in British Columbia (BC) has faced a number of challenges over the past decade. In response to some of those challenges, the government has invested in forest genomic tools. Marker-assisted selection (MAS) is a biotechnological tool that flags desired traits
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The forest sector in British Columbia (BC) has faced a number of challenges over the past decade. In response to some of those challenges, the government has invested in forest genomic tools. Marker-assisted selection (MAS) is a biotechnological tool that flags desired traits on the genome. This tool may assist tree breeders with the early selection of preferred genotypes, reducing the breeding cycle and more accurately and efficiently selecting for improved qualities. However, there is a poor understanding of the perceived acceptability of implementing MAS. Semi-structured interviews and a questionnaire were employed across participants categorized into four groups. It was found that government and industry participants held positive perceptions towards MAS, supporting its use and continued research in BC, and identifying its benefits in forest regeneration and to tree breeders. Environmental non-governmental organizations (ENGOs) and First Nations attitudes lay between neutral and negative. Concerns were most strongly focused on environmental impacts, ecosystem degradation, and reduced genetic diversity, while identified benefits were specific to tree breeders and improved tree resiliency. It was concluded that before MAS can be successfully implemented, an appropriate setting must first be established through improved knowledge of biotechnology and its applications, well-defined policies, and strengthened engagement and consultation with First Nations. Full article
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Open AccessArticle Biomass Accumulation and Net Primary Production during the Early Stage of Secondary Succession after a Severe Forest Disturbance in Northern Japan
Forests 2016, 7(11), 287; doi:10.3390/f7110287
Received: 6 September 2016 / Revised: 9 November 2016 / Accepted: 12 November 2016 / Published: 18 November 2016
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Abstract
Quantitative evaluations of biomass accumulation after disturbances in forests are crucially important for elucidating and predicting forest carbon dynamics in order to understand the carbon sink/source activities. During early secondary succession, understory vegetation often affects sapling growth. However, reports on biomass recovery in
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Quantitative evaluations of biomass accumulation after disturbances in forests are crucially important for elucidating and predicting forest carbon dynamics in order to understand the carbon sink/source activities. During early secondary succession, understory vegetation often affects sapling growth. However, reports on biomass recovery in naturally-regenerating sites are limited in Japan. Therefore, we traced annual or biennial changes in plant species, biomass, and net primary production (NPP) in a naturally regenerating site in Japan after windthrow and salvage-logging plantation for nine years. The catastrophic disturbance depleted the aboveground biomass (AGB) from 90.6 to 2.7 Mg·ha−1, changing understory dominant species from Dryopteris spp. to Rubus idaeus. The mean understory AGB recovered to 4.7 Mg·ha−1 in seven years with the dominant species changing to invasive Solidago gigantea. Subsequently, patches of deciduous trees (mainly Betula spp.) recovered whereas the understory AGB decreased. Mean understory NPP increased to 272 g·C·m−2·year−1 within seven years after the disturbance, but decreased thereafter to 189 g·C·m−2·year−1. Total NPP stagnated despite increasing overstory NPP. The biomass accumulation is similar to that of naturally regenerating sites without increase of trees in boreal and temperate regions. Dense ground vegetation and low water and nutrient availability of the soil in the study site restrict the recovery of canopy-forming trees and eventually influence the biomass accumulation. Full article
(This article belongs to the collection Forests Carbon Fluxes and Sequestration)
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Open AccessArticle A Forest Growth Model for the Natural Broadleaved Forests in Northeastern Korea
Forests 2016, 7(11), 288; doi:10.3390/f7110288
Received: 31 August 2016 / Revised: 13 November 2016 / Accepted: 14 November 2016 / Published: 23 November 2016
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Abstract
While a large sum of timber stock in private forests, especially broadleaved forests, has been ignored by their owners, a rising global concern about climate change and ecosystems has led to a renewed interest in natural broadleaved forest management strategies. This study establishes
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While a large sum of timber stock in private forests, especially broadleaved forests, has been ignored by their owners, a rising global concern about climate change and ecosystems has led to a renewed interest in natural broadleaved forest management strategies. This study establishes the forest growth model for the natural broadleaved forest of Gangwon-do based on the matrix model developed by Buongiorno and Michie. The matrix model by Buongiorno and Michie has been widely applied to study forest population dynamics, especially for uneven-aged forests. To develop an existing matrix model, our approach applies transitional probabilities of forest stands which are calibrated using National Forest Inventory data. Both long and short-term predicted simulation results show that the predicted average tree density and diameter distribution from our model are very close to the stand density and diameter distribution from observed data. Although the model simplifies reality, the results from our study confirm that our models are valid enough to predict the average stand status of the broadleaved forests in Gangwon-do. Full article
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Open AccessArticle Oak Group Planting Produces a Higher Number of Future Crop Trees, with Better Spatial Distribution than Row Planting
Forests 2016, 7(11), 289; doi:10.3390/f7110289
Received: 12 July 2016 / Revised: 9 November 2016 / Accepted: 17 November 2016 / Published: 22 November 2016
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Abstract
Recent studies have reported superior tree quality and comparable tree growth of oaks planted in group compared with row planting. However, a comparative assessment of the potential future crop trees (PFCTs) between group and row planting is still lacking. Here, we compared the
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Recent studies have reported superior tree quality and comparable tree growth of oaks planted in group compared with row planting. However, a comparative assessment of the potential future crop trees (PFCTs) between group and row planting is still lacking. Here, we compared the density and tree quality of planted oaks and other naturally regenerated trees between group and row planting. We assessed whether the distribution of PFCTs fulfills the goal of maintaining a spatially homogenous distribution of such crop trees at the stand level by geospatial analysis. We selected 10 group and row planting stands that were either 14 to 15 or 21 to 22 years old. Tree density in group plantings was significantly higher than in row plantings. Stand basal area was higher in row planting in younger stands but comparable to group planting in older stands. The proportion of trees with straight stems and monopodial crowns was higher in groups than in rows. The density and species’ richness of the PFCTs was significantly higher but the number of oak PFCTs was lower in group than in row plantings. In group plantings, naturally regenerated PFCTs contributed to 43% of total PFCTs, but to only 19% in row plantings. Also, the spatial distribution of PFCTs in group plantings was more uniform than in row plantings. Uniform and homogeneous distribution of the PFCTs in group planting stands can facilitate design and conduct of tending operations. Thus, the group planting technique offers not only cost savings in the establishment phase but also additional benefits, including spreading of risks through increased tree species diversity. Full article
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Open AccessArticle Nutrient Resorption and Phenolics Concentration Associated with Leaf Senescence of the Subtropical Mangrove Aegiceras corniculatum: Implications for Nutrient Conservation
Forests 2016, 7(11), 290; doi:10.3390/f7110290
Received: 31 August 2016 / Revised: 6 November 2016 / Accepted: 17 November 2016 / Published: 22 November 2016
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Abstract
Aegiceras corniculatum (L.) Blanco, a mangrove shrub species in the Myrsine family, often grows at the seaward edge of the mangrove zone in China. In the present study, seasonal dynamics of nutrient resorption and phenolics concentration associated with leaf senescence of A. corniculatum
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Aegiceras corniculatum (L.) Blanco, a mangrove shrub species in the Myrsine family, often grows at the seaward edge of the mangrove zone in China. In the present study, seasonal dynamics of nutrient resorption and phenolics concentration associated with leaf senescence of A. corniculatum were investigated in order to evaluate its possible nutrient conservation strategies in the subtropical Zhangjiang river estuary. It was found that the nitrogen (N) and phosphorus (P) concentrations in mature leaves showed similar seasonal changes with the highest concentrations in winter and the lowest in summer, and were significantly higher than those in senescent leaves. The N:P ratios of mature leaves through the year were found to be less than 14, indicating that the A. corniculatum forest was N-limited. The nitrogen resorption efficiency (NRE) was higher than phosphorus resorption efficiency (PRE), and N resorption was complete. In addition, A. corniculatum leaves contained high total phenolics (TPs) and total condensed tannin (TCT) levels (both above 20%). TPs concentrations in mature and senescent leaves were all inversely related to their N or P concentrations. TPs:N and TCT:N ratios in senescent leaves were significantly higher than those in mature leaves. The obtained results suggested that high NRE during leaf senescence and high TPs:N and TCT:N ratios in senescent leaves might be important nutrient conservation strategies for the mangrove shrub A. corniculatum forest growing in N-limited conditions. Full article
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Review

Jump to: Research

Open AccessReview Thousand Cankers Disease Complex: A Forest Health Issue that Threatens Juglans Species across the U.S.
Forests 2016, 7(11), 260; doi:10.3390/f7110260
Received: 1 September 2016 / Revised: 26 October 2016 / Accepted: 29 October 2016 / Published: 3 November 2016
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Abstract
Thousand Cankers Disease (TCD) is a disease complex wherein the fungus (Geosmithia morbida) is vectored by the walnut twig beetle (WTB, Pityophthorus juglandis). The disease causes mortality primarily of eastern black walnut (Juglans nigra), although other walnut and
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Thousand Cankers Disease (TCD) is a disease complex wherein the fungus (Geosmithia morbida) is vectored by the walnut twig beetle (WTB, Pityophthorus juglandis). The disease causes mortality primarily of eastern black walnut (Juglans nigra), although other walnut and wingnut (Pterocarya) species are also susceptible. Black walnut is native to the Eastern and Midwestern U.S. but is widely planted in western states. Total standing volume in both urban and forested settings is approximately 96 million cubic meters, and is valued at $539 billion. Although native to the Southwestern U.S., the range of WTB has expanded considerably. The spread of G. morbida coincides with that of WTB. TCD was introduced into Tennessee in 2010, and has spread to seven eastern states. Trees infected with TCD exhibit drought-like symptoms, making field detection difficult without molecular and/or morphological methods. The recently sequenced G. morbida genome will provide valuable research tools focused on understanding gene interactions between organisms involved in TCD and mechanisms of pathogenicity. With no chemical treatments available, quarantine and sanitation are preeminent options for slowing the spread of TCD, although biological control agents have been discovered. High levels of black walnut mortality due to TCD will have far-reaching implications for both eastern and western states. Full article
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Open AccessReview Grand Fir Nutrient Management in the Inland Northwestern USA
Forests 2016, 7(11), 261; doi:10.3390/f7110261
Received: 31 August 2016 / Revised: 4 October 2016 / Accepted: 31 October 2016 / Published: 4 November 2016
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Abstract
Grand fir (Abies grandis (Douglas ex D. Don) Lindley) is widely distributed in the moist forests of the Inland Northwest. It has high potential productivity, its growth being nearly equal to western white pine, the most productive species in the region. There
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Grand fir (Abies grandis (Douglas ex D. Don) Lindley) is widely distributed in the moist forests of the Inland Northwest. It has high potential productivity, its growth being nearly equal to western white pine, the most productive species in the region. There are large standing volumes of grand fir in the region. Nutritionally, the species has higher foliage cation concentrations than associated conifers, especially potassium (K) and calcium (Ca). In contrast, it has lower nitrogen (N) foliage concentrations, which creates favorable nutrient balance on N-limited sites. Despite concentration differences, grand fir stores proportionally more nutrients per tree than associated species because of greater crown biomass. Although few fertilization trials have examined grand fir specifically, its response is inferred from its occurrence in many monitored mixed conifer stands. Fertilization trials including grand fir either as a major or minor component show that it has a strong diameter and height growth response ranging from 15% to 50% depending in part on site moisture availability and soil geology. Grand fir tends to have a longer response duration than other inland conifers. When executed concurrently with thinning, fertilization often increases the total response. Late rotation application of N provides solid investment returns in carefully selected stands. Although there are still challenges with the post-fertilization effects on tree mortality, grand fir will continue to be an important species with good economic values and beneficial responses to fertilization and nutrient management. Full article
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